I was doing something stupid today on my high mileage 98 SVT (about 240,000km) and I might have damaged the engine... its my guess.
It was totally empty on the highway so I decided to do a quick to speed blast to see how fast it would go. Around 220km/hr I noticed the check engine come on so I eased off and let it cost down to 100km. I pressed the gas lightly and I could feel that something was not right. Felt a little rough. I exited the highway and right away on the street I could tell that I'm not running on all cylinders. Very rough and lower RPM but I couldnt hear any mechanical type noises from the inside of teh car or see anything strange in the rear view in terms of smoke or loss of fluids. Also no back firing or smell of gas or anything.
So when I come home, I put the car in neutral and rev slowly and I heard a faint knocking type sound at a certain RPM... maybe like 2k but it goes away above or below that RPM. Engine still feels rough. The engine temp is normal and I checked the oil which is synthetic and always has been since I've had the car from 88,000km and it was all there.
I'm thinking that if it was an issue where I had no spark on one cylinder, wouldnt raw fuel go into the cylinder and cause lots of backfiring? If so, then I dont suspect any spark issues. What about a fuel injector going? Is that possible? Would mechanical probs like spun bearings show up as an engine code?
I'm going to pull the plugs and wires and put my old set of wires and plugs which are worn but work. Aside from that, is there anything basic I can try for troubleshooting?
